In particular in the case of production machines, the movement of drives must often be captured by data acquisition and undergo automatic control dependent on process data. For example, the advancement of a screw of a plastics injection-molding machine must be automatically controlled exactly in dependence on the back pressure. Accurate process data acquisition is the basis for the exact reproducibility of the production process carried out by the production machine.
Accurate process data acquisition necessitates high acquisition frequencies and—in the case of analog signals—a high resolution of the analog-digital converters. Furthermore, as many of the process data as possible, preferably all of them, should be acquired time-synchronously, since a time difference between the acquisition of different process data leads to inaccuracies in the subsequent automatic control.
In the prior art, the acquisition of the process data takes place by means of high-speed input modules, by means of which the analog signals to be acquired are digitized. The digitized signals are then transmitted to a higher-level controller, which also supplies the converter with setpoint values.